AI 中文总结
该研究推导了单位量子比特信道的精确不相容性破坏判据，通过操控-联合可测性对应关系得到两量子比特态的相关边界，还为非单位量子比特信道构造父POVM并给出充分条件。
AI 中文摘要
我们研究噪声量子比特信道何时使所有正算子值测度（POVM）联合可测。对每个单位量子比特信道，我们推导了精确不相容性破坏判据，并证明投影测量已确定任意POVM的边界。通过操控-联合可测性对应关系，该结果给出了所有具有最大混合边际的两量子比特态的精确POVM-操控边界，Werner态作为特例被恢复。对于非单位量子比特信道，我们构造了一个一般非对称的父POVM，并得到了显式的充分不相容性破坏条件，该条件进而给出了任意两量子比特态的充分不可操控判据。
英文摘要
We study when a noisy qubit channel renders all positive-operator-valued measures (POVMs) jointly measurable. For every unital qubit channel, we derive the exact incompatibility-breaking criterion and prove that projective measurements already determine the boundary for arbitrary POVMs. Through the steering--joint-measurability correspondence, this result gives the exact POVM-steering boundary for all two-qubit states with maximally mixed marginals, with the Werner states recovered as a special case. For nonunital qubit channels, we construct a generally asymmetric parent POVM and obtain an explicit sufficient incompatibility-breaking condition, which in turn yields a sufficient unsteerability criterion for arbitrary two-qubit states.
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